(Reuters Health) - Obese people with sleep apnea, a common nighttime breathing disorder, may live longer when they use a machine to help keep their airways open while they sleep, a recent study suggests.

After following obese patients with sleep apnea for about 11 years, researchers found those who used the nighttime breathing aid were 42 percent less likely than those who didn’t use the devices to die of any cause.

Apnea that isn’t properly treated has been linked with excessive daytime sleepiness, heart attacks, heart failure and an increased risk of premature death. Often, patients are prescribed treatment with masks connected to a machine that provides continuous positive airway pressure (CPAP), which splints the airway open with a steady airstream so the upper airway can’t collapse during sleep. Some patients receive positive airway pressure (PAP) devices that vary the amount of air pressure for inhalation and exhalation instead of keeping it constant.

“In patients with sleep apnea, there is a poor oxygenation of the body during sleep,” said lead study author Dr. Quentin Lisan of the Paris Cardiovascular Research Center in France.

“This has several consequences, including increased risk of cardiovascular diseases,” Lisan said by email. “PAP therapy allows a better oxygenation of the body during sleep, hence lowering the risk of these associated conditions, which in turn might decrease mortality.”

For the current study, the researchers examined data on 81 obese sleep apnea patients who were prescribed PAP treatments and a control group of 311 apnea patients who were not prescribed this type of treatment.

After an average follow-up period of around 11 years, a total of 12 patients prescribed PAP died, as did 84 people who weren’t prescribed PAP, Lisan’s team reports in JAMA Otolaryngology-Head & Neck Surgery.

All of the patients in the study had severe apnea, and it’s possible that results might be different for people with milder forms of the nighttime breathing disorder, Lisan noted.

One drawback of PAP machines is that they can be noisy and uncomfortable, and sometimes make it difficult for patients to fall or remain asleep.

Some patients who can’t tolerate wearing the breathing masks all night may use an alternative apnea treatment known as mandibular advancement devices, which open up space in the airway by pushing out the lower jaw bone to make it less likely that the upper airway collapses during sleep.

The study wasn’t designed to prove whether or how PAP machines might help apnea patients live longer. It also didn’t test survival odds with PAP against those with alternative apnea interventions.

One limitation of the results is that it’s not clear how consistently patients on PAP used the machines as prescribed, which can affect the treatment’s effectiveness.

“Patients must be adherent to PAP for the treatment to work, and we know from other studies that the more adherent they are to the device, the more disease benefit they will receive,” said the author of an accompanying commentary, Dr. Clete Kushida of the Stanford Sleep Medicine Center in Redwood City, California.

“We do not exactly know why PAP reduces mortality risk, but PAP may have reduced the mortality caused by factors such as heart attacks, stroke, high glucose levels and high blood pressure,” Kushida said by email.

When patients can’t tolerate PAP, they should see their doctor to see if the settings can be adjusted to make it more comfortable, said Marie-Pierre St-Onge, a sleep researcher at Columbia University Irving Medical Center in New York City who wasn’t involved in the study. They may do better with different pressure settings, or with a different PAP machine.

“Some people need more or less pressure to keep the airways open and a sleep test in the laboratory can help us determine what that optimal pressure is,” St-Onge said by email. “Too high is uncomfortable, too low will not be effective.”